Conventional lattice girders are described, for example, in DE 197 11 627 C 2. The lattice girder has three parallel boom members which are connected to each other by V-shaped truss braces. The truss braces are bent at the portion where the truss brace and boom member are connected. The truss braces and boom members are welded together at these portions. A cross-tie is provided to hinder a zip-like failure of this weld.
EP 0073 733 A 1 describes a lattice girder having three parallel boom members which are spatially secured relative to each other by means of internal one-piece bracing elements. These bracing elements have very narrow bending radii which can be used for comparatively thin elements only.